Hey, this is the net, right? It's all to be expected. Except what first looks like a frat house stunt suddenly turns into something more malicious.

Hackers recently bombarded the Epilepsy Foundation's Web site with hundreds of pictures and links to pages with rapidly flashing images.

The breach triggered severe migraines and near-seizure reactions in some site visitors who viewed the images. People with photosensitive epilepsy can get seizures when they're exposed to flickering images, a response also caused by some video games and cartoons.

This gets me really angry.

I understand that the sheer volume of people online makes this sort of idiocy more likely to happen. But I can't shake an underlying feeling of distaste at the internet morons who create a disproportionate amount of havoc online and - largely through their addiction to malice - ruin it for everyone else.

Griefers are something we've all learned to deal with online, whether it's the attention-seeking mob called Anonymous, comment thread trolls or the flying penises of Second Life. But even those who have helped bring this culture about disavow it: at ROFLCon a couple of weeks ago it was interesting to hear moot, the owner and creator of 4Chan, say that he was far from proud of a lot of what happens on the site.

My problem isn't that griefers exist. That's life. What does make me angry is that these are the people who represent us in the world.

Every time a griefer or troll lashes out, somebody else thinks anyone into internet culture must be brain dead or anti-social. Just now I opened my mail and found a copy of Lee Siegel's paperback "Against the Machine (subtitle: "Being human in the age of the electronic mob". I haven't looked further inside yet (I try to avoid trolls in any medium), but from past form I suspect that he may end up picking out the worst instances of behaviour to describe the entire culture.

This is what happens when griefers become so visible. But how do we stop it?